System of alternating-current transmission.



' No. 655,34l. Patented Aug. 7, I900.

J. H. F. GURGES. SYSTEM OF ALTEBNATING CURRENT TRANSMISSION.

(Application filed Oct. 11, 1899.)

(No Model.)

LLLL l NITED, STATEs' PATENT Crricn.

JOIIANNES HEINRICH FRIEDRICH GCRGES, OF BERLIN, GERMANY, ASSIGNOR THESIEMENS & IIALSKE ELECTRIC COMPANY OF AMERICA, OF CHICAGO, ILLINOIS.

sYsTEM F ALTERNATINGECURREN'I TRANSMISSION.

srEcirIcATIoN forming part of Letters Patent No. 655,341, dated August'7, 1900.

Application filed October 11, 1899. Serial No. 733,294. (No model.)

To all whom it may concern: advantage, as in actual practice where dryBe it known that I, JOHANNEs HEINRICH Condensers are employed foreffecting the FRIEDRICH GORGES, a subject of the Emperor regulation ofmotors for performing power of Germany, residing at Berlin, Germany,work, and where these condensers have been 5 have invented a certain newand useful Imincluded directly in a bridge-circuit, their prove'ment inSystems of Alternating-Current size has had to be great to perform thede- Transmission, (Case No. 243,) of which the sired work, and I am thusenabled not only following is a full, clear, concise, and exact toemploy a single condenser to furnish the description, reference beinghad to the accapacity for opposite sides of a bridge-circuit,

1o companying drawings, forming a part of this but am enabled wherepower-motors are to specification. be regulated greatly to reduce thesize of the My invention relates to alternating-currentcondenser.

transmission systems, and has for its object I will explain my inventionmore particuthe provision of improved means for adj ustlarly byreference to the accompanying draw- 15 ing the difference in phasebetween the indeing, in whichpendent field-windings of induction-motorsFigure 1 illustrates a diagrammatic aror the fields of meters employinginduction rangement of a system in which the phase motive members foroperating the indicators between the exciting-circuits of the motor isor recording elements. regulated by means of condensers in opposite 20 Awell-known means for effecting the resides of a Wheatstone-bridgecircuit. Fig. 2

quired phase adjustment is that in which a is a diagram illustrating themathematical 7o WVheatstone bridge is employed suitablyconproblemsemployed. Fig. 3 illustrates my nected in circuit with one of thefield-windimproved means for regulating the phase difings or sets offield-windings of the motor, ference between the exciting-circuits ofthe 25 two sides of the bridge-circuit containing remotor.

,tardation or impedance coils and the remain- Like letters indicate likeparts throughout ing two sides of the bridge-circuit containing thedifferent figures. condensers. Two condensers are thus ref Fig. 1,illustrating the means heretofore emquiredin connection with eachbridge-circuit; ployed, shows a source of single-phase alter- 0 and itis the prime object of my invention so nating current Ct, supplyingcurrent to the to associate asingle condenser with the bridgemains b b.In parallel branches between the circuit that the desired capacityin twoof the mains are included the sets of windings c opposite sides of theWheatstone bridge may and (l. The motor illustrated is a powerbe securedby the employment of this single motor. It is obvious that if the motorwere 3 5 condenser. This result I am enabled to acemployed in awattmeter the branch circuits,

complish through the agency of a transformer including theexciting-windings of the motor, whose primary windings form the windingswould not be in parallel bridges between the in the opposite sides ofthe bridge-circuit in mains. The Wheatstone bridge is directly which thephase is to be advanced, the sec connected between the mains, twoopposite 4o ondary of the transformer having two windsides of the bridgeincluding the impedance ings in inductive relation with the aforesaid orretardation coils and the remaining oppo- 9o windings, a condenser beingincluded in this site sides including the condensers ff. Thesecondarywinding, which then, obviously, is condensers and theretardation-coils serve to capable of advancing the phase in theprisecure the proper adjustment of the phase at 45 mary windings. y theterminals g and h, as is well known. A

p By means of my invention I am enabled to diagonal of the Wheatstonebridge connects 5 use a small condenser, which, cooperating theterminals g and h, this diagonal includwith the transformer-coils,serves properly to ing the windings c of the motor. furnish the desiredcapacity. This is a great In the preferred embodiment of my invention Ihave replaced the condensers ffby coils 7t 70, Fig. 3, of thetransformer Z. This transformer is constructed with three windings,thetwo primary windings 7t 7tbeing included in opposite branches of thelVheatstone bridge and the secondary winding m being connected directlyin circuit with a condenser f. I also preferably employ a divided corea, upon which I place both of the retardation-coils e e. \Vith thecondenser arranged as thus shown I am enabled to secure the requiredcapacity without resorting to the use of a large number of condensersand can thus secure the additional advantage of a high-power factor dueto the use of condensers in the IVheatstonc-bridge circuit. It isessential to have the power factor as high as possible in meters and inpower-motors which are operated as two-phase meters from a single-phasesupply-circuit. The current required is hereby greatly reduced anddisturbances on the supply-circuit are not so frequent and deleterious.The use of condensers also materially reduces the amount of power whichis uselessly consumed in the bridge-circuit to a minimum, the powereonsumed very nearly approaching the true power necessary to excite thecoils of the instrument included therein.

In previous systems in which condensers were not employed the actualpower traversing the shunt-circuit was greater than that necessary inthe operation of the shunt-coils, as there was always some electricalpath which did not include the shunt-coils through which current mightpass from one main to another, the power lost in this path being wasted.In the present invention, as will be clear from the phase-diagram, thepower lost in the sides of the VVheatstone bridge is de creasedmaterially, as there are no artificial resistances employed therein.This will be apparent from Fig. 2, in which the voltages and currents inthe separate circuits are graphically represented. The pressures cacross the self-inductive branches 6 and the pressures c across thecapacity branches f form a closed parallelogram, the impressed pressurec being the pressure across the extremities thereof. The diagonalpressure e is the pressure across the middle terminals g h of thenetwork. The current i in the diagonal branch lags behind its pressure eby an angle (7). The current 2}- in the capacity branch of the circuitleads its pressure by an angle 0;. The geometrical co1nbination of thesetwo currents gives the current 1'. in the self-inductive branch of thebridge. I preferably use equal inductances and equal capacities in theopposite branches. The total current i traversing the bridge-circuitwill then be equal to the geometrical sum of the current 11- in thecapacity branch and the current 2' in the self-inductive branch thereof.This current i lags behind the impressed pressure by an angle 9, whichis exceedingly small, and thereby insures a highpower factor. Thecurrent 1' is seen to lag behind its pressure 6., nearly ninety degrees,thereby minimizing the power absorbed in the self-inductive branches.The lag of the current is represented by the angle ninety degrees minusI, the line r being an extension of the line a, and forming a rightangle with the line r The power supplied to the bridgecircuit is equalto the product of the voltage supplied and that portion of the currentused which is in phase with the pressure or, mathematically expressed, amultiplied by i cos S. It will be seen that the amount of power used isinversely proportional to the size of the angle 50, and therefore it isessential that the capacity in the circuit be as large as possible. Theuseful power employed is equal to the product of the pressure across thediagonal branch and the current in this branch which is in phase withits pressure or, mathematically expressed, e multiplied by 21 cos 1 Tohave the useful power bear a high relation to the supplied power, it iswell to have the diagonal pressure he as nearly equal to the impressedpressure as possible.

The amount of current 2' required to operatea single-phase motor on atwo-phase current is equal to the geometrical sum of the current inecessary for operating one phase and the current i necessary to operatethe other phase. The current i bears the ratio 6. c to the current/1 andlags behind the impressed pressure by an angle 1. The total powerrequired would again be equal to the product of the impressed pressureand the current in phase with it, or c, multiplied by 6., cos (n. Thisis about one hundred and fifty per cent. of the power necessary tooperate the motor as a single-phaser; but as the motor will give almostdouble the power when operated on a two-phase current it is obvious thata great saving results by the use of this system. I do not wish to belimited to the number of secondary circuits or the number of condensersemployed in all instances, as the number may in some embodiments bevaried.

I have herein shown and particularly de scribed the preferred embodimentof my invention; but it is apparent that changes in the specificarrangement thereof may readily be made without failing to realize thespirit of the invention shown, and I therefore do not wish to be limitedto the precise arrangement shown; but

I claim as new and desire to secure by Letters Patent-- 1. Thecombination with a source of alternating current, of a motor having aplurality of energizing-windings a Wheatstone bridge for effecting thephase adjustment of the energizing-windings and a secondary circuitininductive relation with a winding of the lVheatstone bridge andincluding a condenser, substantially as described.

2. The combination with a source of alter nating current, of a motorhaving two sets of IIO windings supplied thereby, a Wheatstone bridgeincluded in circuit with one of the sets of windings, retardation-coilsincluded in opposite sides of the Wheatstone-bridge circuit, atransformer, two primary windings thereon included in the remainingopposite sides of the Wheatstone-bridge circuit, a secondary circuit ininductive relation to the said windings of the transformer, and acondenser in the said secondary circuit, whereby the phase is advancedin the said primary windings, substantially as described.

3. The combination with a source of alternating current, of a motorhaving two sets of windings supplied thereby, a Wheatstone bridgeincluded in circuit with one of the sets of windings, retardation-coilsincluded in opposite sides of the Wheatstone-bridge circuit, atransformer, two primary windings thereon included in the remainingopposite sides of the WVheatstone-bridge circuit, a secondary circuit ininductive relation to the said windings of the transformer, and acondenser in the said secondary circuit, whereby the phase is advancedin the said primary windings, the set of windings of the motor connectedwith the Wheatstone bridge being included in a diagonal conductor acrossthe W'heatstoncbridge circuit, substantially as described.

4. The combination with a source of alternating current, of a motorhaving two sets of windings supplied thereby, a Wheatstone bridgeincluded in circuit with one of the sets of windings, retardation-coilsincluded in opposite sides of the Wheatstone-bridge circuit, said coilsbeing mounted upon the same core, a transformer, two primary windingsthereon included in the remaining opposite sides of theWheatstone-bridge circuit, a secondary circuit in inductive relation tothe said windings of the transformer, and a condenser in the saidsecondary circuit, whereby the phase is advanced in the said primarywindings, the set of windingsof the motor connected with the Wheatstonebridge being included in a diagonal conductor across theWVheatstonebridge circuit, substantially as described.

5. The combination with a set of excitingcoils of a motor, of aWheatstone-bridge circuit connected therewith, impedance-coils includedin opposite sides of the WVheatstonebridge circuit, a transformer, twoprimary windings thereon included in the remaining opposite sides of theWheatstone-bridge circuit, a secondary circuit in inductive relation tothe said windings of the transformer, and a condenser in the saidsecondary circuit for advancing the phase in the primary windings,substantially as described.

6. In combination with a Wheatstonebridge circuit, a set ofexciting-coils of a motor included in the diagonal of saidWheatstone-bridge circuit, retardation coils in cluded in two oppositesides of the WVheat stone-bridge circuit, a transformer, two primarywindings thereon included in the remaining opposite sides of theWheatstonebridge circuit, a secondary circuit in inductive relation tothe said windings of the transformer, and a condenser in the saidsecondary circuit, whereby the phase is advanced in the said primarywindings, substantially as described.

7. The combination with a source of alternating current, of a motorhaving two sets of windings supplied thereby, a Wheatstone bridgeincluded in circuit with one of the sets of windings, retardation-boilsincluded in opposite sides of the Wheatstone-bridge circuit, atransformer, a primary winding thereon included in a side of theWheatstone bridge circuit, a secondary circuit in induc tive relation tothe said winding of the transformer, and a condenser in the saidsecondary circuit, whereby the phase is advanced in the said primarywinding, substantially as described.

8. The combination with a source of alternating current, of a motorhaving two sets of windings supplied thereby, a Wheatstone bridgeincluded in circuit with one of the sets of windings, retardation-coilsincluded in opposite sides of the Wheatstone-bridge circuit, atransformer, a primary winding thereon included in a remaining side ofthe Wheatstone-bridge circuit, a secondary circuit in inductive relationto the said winding of the transformer, and a condenser in the secondarycircuit, whereby the phase is advanced in the said primary winding, theset of windings of the motor connected with the Wheatstone bridge beingincluded in a diagonal conductor across the Wheatstone-bridge circuit,sub stantially as described;

9. The combination with a source of alternating current, of amotorhaving a plurality of energizing-windings, a Wheatstone bridge foreffecting the phase adjustment of the energizing windings, and acondenser associated with but extraneous toa branch of the Wheatstonebridge to modify the phase of current flowing therethrough,substantially as described.

In witness whereof I hereunto subscribe my name this 19th day ofSeptember, A. D. 1899.

JOHANNES HEINRICH FRIEDRICH GilRGES.

Witnesses:

HENRY HASPER, WOLDEMAR HAUPT.

